Figure 5. Primary rat microglia recognized SWCNT functionalized with PS but not with PC.

A. Scanning electron micrographs of microglia treated with PS-coated SWCNT in vitro. Microglia (1.5×10⁵ cells/ml) were incubated for 2 h with PC- or PS-coated SWCNT. At the end of incubation macrophages were washed and fixed for SEM. (Note: The red arrows in all the electron micrographs in figure 5 point SWCNT). B. Transmission electron micrographs of primary microglia exposed to SWCNT in vitro. Microglia (1.5×10⁵ cells/ml) were incubated with PC- or PS-coated SWCNT. At the end of incubation microglia was washed and fixed for TEM. a) Microglia exposed to PS-coated SWCNT; b) Quantitative assessments of SWCNT phagocytosis by RAW 264.7 macrophages. A total of 60 cells from each sample type were analyzed by TEM. Data are mean±S.D., n = 3, *p<0.05, PS-coated SWCNT vs SWCNT, PC coated SWCNT and PS-coated Annexin V–treated SWCNT. C. In vitro assessment of uptake of SWCNT coated with NBD-PS or NBD-PC by microglia. Microglia (1.5×10⁵ cells/ml) were incubated with NBD-PC- (a), NBD-PS-coated SWCNT (b) or NBD-PS-coated/Annexin V treated SWCNT (c). 1 – bright field image; 2 – blue fluorescence image, Hoechst 33342; 3 – green fluorescence image, NBD-labeled phospholipids; 4 – overlap of blue and green fluorescence images with image under bright field. d) Annexin V treatment of NBD-PS-coated SWCNT prevents their engulfment by microglia. Quantitative evaluation of cell number with engulfed SWCNT. Data are mean±s.d., n = 4. *p<0.05, NBD-PS-coated SWCNT vs NBD-PC-coated SWCNT and NBD-PS-coated Annexin V treated SWCNT.